非髄膜上皮系の間葉系腫瘍

Mesenchymal and Non-meningothelial Tumors Involving the Central Nervous System

Point

・孤立性線維性腫瘍/血管周皮腫という名称が廃止され，孤立性線維性腫瘍（SFT）となった．

・SFTは核分裂数と壊死によりgrade 1〜3に分類される．

・遺伝子異常によって規定される3つの新たな原発性頭蓋内肉腫の診断名が導入された．

　In the World Health Organization Classification of Brain Tumors Fifth Edition, mesenchymal non-meningothelial tumors involving the central nervous system are divided into three major categories: soft tissue tumors, chondro-osseous tumors, and notochordal tumors. Soft tissue tumors are classified into four groups: fibroblastic and myofibroblastic tumors, vascular tumors, skeletal muscle tumors, and tumors of uncertain differentiation. This article will focus on solitary fibrous tumors（SFTs）, which are frequently encountered clinically and continue to undergo classification revisions in the 5^th edition, and outline the three newly added histological diagnoses. Although SFTs and hemangiopericytomas occur throughout the body, including the central nervous system, nomenclatures have been different between the classifications of“Tumours of Soft Tissue and Bone”and“Tumours of the Central Nervous System.”The latest nomenclature is“SFT”in accordance with the nomenclature of bone and soft-tissue tumors. In addition, three new diagnoses, which are intracranial mesenchymal tumor FET-CREB fusion-positive, CIC-rearranged sarcoma, and primary intracranial sarcoma DICER1-mutant, have been defined based on genetic abnormalities in tumors of uncertain differentiation.